Nurses and other medical professionals all have personal preferences in terms of giving injections, including intramuscular injections. Each takes a slightly different approach, often combining several intramuscular injection techniques based on training and professional experience. Some of the most common techniques include the traditional dart technique and the Z track, bunching, air bubble, and the aspiration techniques. Recommended techniques vary, depending on the specific injection site and cultural preferences. For example, the air bubble technique is popular in the United States but not recommended in the United Kingdom.
All intramuscular injection techniques involve similar principles. One of several available large muscle areas are chosen, based on the age and physique of the patient. Once injected, the syringe ideally sits at a 90-degree angle, with the needle inserted directly into the muscle tissue. Differences in techniques typically center on how the injection site and syringe are prepared prior to injection, with most differences intended to decrease pain or discomfort for the patient.
Traditional intramuscular injection techniques involve stretching the skin over the proposed injection site and inserting the needle like a dart. A nurse or other medical professional holds the syringe in the dominant hand, while using the other hand to stretch out the skin around the site in multiple directions. After the needle is inserted, the skin is released. Most users of the traditional dart technique cite desensitization of surrounding nerve endings as the primary reason for choosing this method.
Similar to traditional intramuscular injection techniques, the Z track method also stretches the skin around the injection site. Rather than stretching in several directions, the Z track technique pulls the skin downward or to one side, prior to inserting the needle. Like traditional injection techniques, this method moves the skin and other tissues slightly, to give better access to muscle tissues while alleviating pain for the patient. Unlike the traditional method, however, the Z track technique requires holding the stretched skin until the needle is removed.
Both the air bubble technique and the aspiration technique can be combined with other methods for giving an intramuscular injection. The air bubble technique evolved from a time when manufacturers made syringes with glass barrels. Medication is drawn into the syringe, leaving a small air bubble in the barrel, which helps to seal the injection site, preventing medication from leaking out of the muscle tissue. Aspiration simply involves pulling back on the syringe plunger after the needle enters the skin, but before injecting the medication, to check for blood or other indications of a pierced blood vessel.
Other intramuscular injection techniques are also employed depending on several factors. Older patients and patients who have less muscle mass sometimes require using a bunching technique, rather than traditional dart or Z track techniques. With this technique, the nurse or other professional bunches up skin and muscle tissue in one hand, while injecting the medication with the other hand. Bunching up smaller tissues creates a temporarily larger area, making it easier to ensure the medication is injected correctly.